The 851st Strategic Missile Squadron is an inactive United States Air Force unit. It was last assigned to the 456th Strategic Aerospace Wing, stationed at Beale Air Force Base, California. It was equipped with the HGM-25A Titan I intercontinental ballistic missile, with a mission of nuclear deterrence. It was the last Titan I squadron to achieve alert status on 1 February 1961. The squadron was inactivated as part of the phaseout of the Titan I on 25 March 1965.

The 490th Bombardment Group is a former United States Army Air Forces unit. The group was activated in October 1943. After training in the United States, it deployed to the European Theater of Operations and participated in the strategic bombing campaign against Germany from 31 May 1944 to 20 April 1945, losing 22 aircraft while flying more than 5,000 sorties. Following V-E Day, the group returned to the United States, where it was inactivated in November 1945.